Active mechanism
Samsca acts by excretion of free water (water without sodium and other electrolytes), which is known as aquaresis. This distinguishes it from natriuresis, in which both sodium and water are excreted.
Samsca inhibits the binding of vasopressin to the V2 receptors in the kidney’s collecting duct, which increases the excretion of free water and thereby results in increase sodium concentrations.
Click play to view the Samsca video.